I have a chequer plate door liner for a disco 1, and it most certainly does not fit on a disco 2!
The shape is the same, but the position of the opening lever, and closing handle are very different. (due to the direction of the third row of seats.)
I ended up having a door panel made for me out of plain ali sheet. You need lots of padding behind it, and fix it down well or it will rattle like a good 'un.
If anyone wants to make an offer on a Disco 1 chequerplate door liner, drop me a line.
Ed